This difference can therefore be explained by the fact that the summit can swing freely while the foot of the mountain is firmly anchored. The amplification of seismic energy on steep mountains plays an important role in assessing the risk of rock and slope instabilities in an earthquake.
The scientists around Samuel Weber, who previously worked at the Technical University of Munich and is now doing research at the WSL Institute for Snow and Avalanche Research (SLF), installed seismometers around the Matterhorn that felt the pulse of the detached mountain in the Valais Alps. They placed measuring stations directly on the summit, along the ridge and at the foot of the mountain. According to this, the 4470 meter high summit moves back and forth by a few nanometers to micrometers in a good two seconds.
The oscillation occurs on the one hand in the north-south direction and at approximately the same frequency of 0.42 Hertz in the east-west direction, as the team reports in the specialist magazine “Earth and Planetary Science Letters”. The researchers were unable to observe seasonal fluctuations, triggered for example by changes in temperature or ice.
Seismologists from the Swiss Seismological Service carried out similar measurements on the Great Mythen. Accordingly, similar vibration patterns were found on this “miniature Matterhorn”, but the frequency on this 1898 meter high mountain was around four times higher than that of its big brother in the Valais.
https://doi.org/10.1016/j.epsl.2021.117295